115 articles
Anti-nuclear antibody negative
Anti-nuclear antibody negative (ICD-11 MA14.13, ANA-) is a lab finding of no antinuclear antibodies detected. It lowers the likelihood of autoimmune disease but never rules it out; ENA antibodies occur in about 8% of ANA-IIF-negative suspected CTD cases.
Anti-nuclear antibody positive
Anti-nuclear antibody positive: a screening result showing serum autoantibodies to nuclear antigens, detected by HEp-2 immunofluorescence or solid-phase assay; common in healthy people, interpreted by titer, pattern, and clinical context.
Antibody-dependent complement deposition assay
The antibody-dependent complement deposition (ADCD) assay is a bead-based flow cytometry serology assay that quantifies complement proteins deposited by antibodies in serum or plasma, reported in 2019.
Anticitrullinated protein antibody positive
ACPA positive (anti-CCP positive): blood autoantibodies against citrullinated peptides, strongly associated with rheumatoid arthritis; pooled sensitivity 67%, specificity 95%, detectable years before RA onset, also positive in some other diseases.
Antitumor Drug Screening Assays
Antitumor drug screening assays are laboratory methods for testing how well anticancer drugs and biologic inhibitors work, ranking candidate compounds before toxicology studies or clinical trials.
Bacilloscopy
Bacilloscopy, also called sputum smear microscopy or acid-fast bacillus (AFB) testing, is microscopic examination of stained smears to detect Mycobacterium tuberculosis; Ziehl-Neelsen or auramine staining, 25-75% sensitivity versus culture, high specificity.
Bacterial Load
Bacterial load is the quantity of bacteria in a sample such as blood, sputum, or a wound, measured by culture or qPCR and often linked to mortality risk.
Bacteriological Techniques
Bacteriological techniques are the laboratory methods used to detect, grow, and identify bacteria, ranging from Gram staining and culture to PCR and MALDI-TOF mass spectrometry.
Bentiromide
Bentiromide (BT-PABA, brand Chymex) is a synthetic peptide, FDA-approved in 1983, used orally to test exocrine pancreatic function: chymotrypsin cleaves it to PABA, measured in urine; now discontinued.
Biological Preservation
Biological preservation, chiefly cryopreservation, maintains cells, tissues, germplasm, biospecimens, and forensic evidence in usable condition. Key facts: 1949 glycerol discovery, vitrification, −80 °C and liquid nitrogen storage, ISBER and ISO biobanking standards, NISTIR 7928 evidence handbook.
Blood Chemical Analysis
Blood Chemical Analysis: measurement of electrolytes, glucose, proteins, enzymes, and fats in blood, also called blood chemistry testing or metabolic panels (BMP, CMP), used to assess kidney, liver, and organ function and diagnose disease.
Blood Specimen Collection
Blood specimen collection, usually called phlebotomy, is the drawing of a blood sample to assess its overall character or measure its cells, chemicals, or gases in the laboratory.
Blood Volume Determination
Blood Volume Determination: indicator-dilution measurement of circulating blood volume using 51Cr-labeled red cells and radioiodinated albumin; also called blood volume analysis, expressed in L/kg.
Body Weights and Measures
Body Weights and Measures is a MeSH descriptor (D001837) under Anthropometry indexing body measurement topics such as BMI, height, weight, waist circumference, and skinfold thickness, and the standardized anthropometric practice those terms cover.
Cas12a assay
A Cas12a assay is a CRISPR-based nucleic acid detection method in which target-bound Cas12a cuts nearby single-stranded DNA reporters, giving a fluorescent signal that detects viruses, bacteria, and cancer DNA.
CD4 Lymphocyte Count
CD4 lymphocyte count (CD4+ count, T4 count, helper T cell count): flow-cytometric blood test measuring CD4 T cells, the key immune-function marker in HIV care, guiding OI prophylaxis and ART monitoring.
CD4-CD8 Ratio
CD4-CD8 ratio (T4-T8 ratio): laboratory measure of helper versus cytotoxic T lymphocytes, normally 1.5-2.0; inverted in HIV, slow to normalize on ART, and prognostic for mortality below 0.5.
Cell Count
Cell count: the number of cells of a specific kind per unit volume or area. Also called cell enumeration or cell density; measured manually by hemocytometer or automatically by Coulter-principle and optical instruments.
Cell Migration Assays, Leukocyte
Leukocyte cell migration assays, including the Boyden/transwell filter assay, under-agarose, Zigmond and Dunn chambers, and microfluidic devices, measure white blood cell chemotaxis, chemokinesis, and haptotaxis in vitro.
Chemosensitivity assay
A chemosensitivity assay, also called chemosensitivity testing, is a laboratory method measuring how cultured tumor cells respond to chemotherapy drugs, used to guide individualized treatment and drug development.
Clinical Chemistry Tests
Clinical chemistry tests measure analytes such as glucose, creatinine, and electrolytes in blood, urine, and other body fluids to assess health and organ function. Rooted in Wöhler's 1828 urea synthesis, the field uses reference intervals, quality standards, CLIA regulation, and traceability.
Clinical Enzyme Tests
Clinical enzyme tests are laboratory analyses measuring enzyme activity or levels in body fluids or tissues, used to assess disease risk, diagnose, and monitor disease.
Clinical Laboratory Improvement Amendments
The Clinical Laboratory Improvement Amendments (CLIA) are US federal statutes passed in 1988 that set quality standards for clinical laboratory testing on human specimens such as blood and tissue.
COLD-PCR
COLD-PCR, short for co-amplification at lower denaturation temperature-PCR, is a modified polymerase chain reaction that enriches minority mutant alleles for detection, introduced in 2008 and used mainly in cancer mutation testing.
Complement Hemolytic Activity Assay
Complement Hemolytic Activity Assay (CH50, total hemolytic complement): functional blood test measuring total classical and terminal complement pathway activity by lysis of antibody-sensitized sheep red blood cells; used to screen complement deficiency and monitor lupus.
Conditioned Culture Media
Conditioned culture media (conditioned medium, CCM) is cell culture medium enriched with the secretome of cultivated cells, used for co-culture signaling studies, extracellular vesicle isolation, and cell-free regenerative therapies, with known purity and standardization limits.
COVID-19 Nucleic Acid Testing
COVID-19 nucleic acid testing (NAAT, RT-PCR) detects SARS-CoV-2 RNA by amplification; the reference-standard diagnostic, pooled point-of-care sensitivity 92.8%, specificity 97.6%, more sensitive than antigen tests.
Decalcification Technique
Decalcification technique: histological removal of calcium minerals from bone and teeth (MeSH D003648) using acids such as nitric or formic acid or the chelator EDTA, balancing speed against tissue, antigen, and nucleic acid preservation.
Dental Stress Analysis
Dental Stress Analysis is a dental research field, indexed by the National Library of Medicine since 1972, that measures how forces distribute through teeth, bone, implants, and restorations.
DNA Contamination
DNA contamination is the unintentional introduction of exogenous DNA into a sample, PCR reaction, or evidence item, also called adventitious introduction in forensic practice; distinguished from background DNA, controlled through segregation, clean rooms, negative controls, and elimination databases.